Generally, mobile communication systems have been developed to provide a voice service while securing an activity of a user. However, mobile communication systems have gradually been extended from a simple voice service to a data service. At present, mobile communication systems have been developed to provide a high-speed data service. However, since a resource shortage phenomenon may occur in an existing mobile communication system that provides high-speed services, a more developed mobile communication system has been required.
To meet the requirement, standardization of the long term evolution (LTE) system in the 3rd generation partnership project (3GPP) is being developed as a next-generation mobile communication system. The LTE is a technology of implementing fast packet based communication having a maximum transmission rate of 100 Mbps or so. For this purpose, several schemes have been discussed. For example, a scheme of reducing the number of nodes located on a communication path by simplifying network architecture, a scheme of approaching radio protocols to a radio channel, etc.
Meanwhile, one of the LTE/LTE-advanced (LTE-A) technologies based on a packet switched scheme, a voice over LTE (VoLTE) may implement voice communication like the existing 3rd wireless communication based on a circuit switched scheme.
Unlike a voice over Internet protocol (VoIP) that may be used in a mobile messenger application, the VoLTE allows telecommunication companies (or common carriers) to control a transmission rate depending on a network state and perform management to prevent communication from being disconnected. By doing so, the VoLTE may have a faster connection rate and a higher quality of communication than the circuit switched scheme.
However, the VoLTE has the problem of the low data rate used in the existing 3rd wireless communication and a signal arrival coverage smaller than that of the voice communication dedicated standard based on the circuit switched scheme.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.